Re: [PATCH] gnumach: vm_allocate_contiguous: Allow small power 2 alignments

[Samuel Thibault]

Applied, thanks!

Damien Zammit, le dim. 21 août 2022 06:58:54 +0000, a ecrit:
> This allows contiguous allocations aligned to values
> smaller than one page, but still a power of 2,
> by forcing the alignment to be to the nearest page.
> 
> This works because PAGE_SIZE is a power of two.
> 
> ---
>  vm/vm_user.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/vm/vm_user.c b/vm/vm_user.c
> index ad1fa75d..3ef64dfc 100644
> --- a/vm/vm_user.c
> +++ b/vm/vm_user.c
> @@ -590,6 +590,10 @@ kern_return_t vm_allocate_contiguous(
>       if (palign == 0)
>               palign = PAGE_SIZE;
> 
> +     /* FIXME: Allows some small alignments less than page size */
> +     if ((palign < PAGE_SIZE) && (PAGE_SIZE % palign == 0))
> +             palign = PAGE_SIZE;
> +
>       /* FIXME */
>       if (palign != PAGE_SIZE)
>               return KERN_INVALID_ARGUMENT;
> --
> 2.34.1
> 
> 
>